Such known clutches have both a rotor part which is provided with a friction lining and a rotor part which is connected in a rotationally fixed fashion to a first shaft and on which an electric coil is arranged on the side facing away from the friction lining, and an armature plate which is connected in a rotationally fixed but axially moveable fashion to a second shaft. In this context, in the engaged state a torque which is dependent on the coil current is transmitted from the first shaft to the second shaft. Therefore, if it is desired to maintain the force flux between the shafts, current has to flow constantly through the coil of the clutch.
DE 102 25 580 A1 discloses an electromagnetic clutch for use within a drive train for automatically activating the tailgate of a motor vehicle on whose rotor part a permanent magnet is arranged. This ensures that the tailgate of the motor vehicle is held securely in each intermediate position when the coil is currentless. However, in this clutch a current must flow through the coil continuously in order to disconnect the clutch. Essentially force-free emergency activation of the corresponding tailgate is therefore not possible.